(1) Field of the Invention
The present invention relates to a protective tape separating method for joining a separating adhesive tape or the like while pressing its non-adhesive face with a joining member onto protective tape joined to a surface of a semiconductor wafer held from its back face by a ring frame through a supporting adhesive tape, and separating the separating adhesive tape or the like, thereby separating the protective tape together with the separating adhesive tape or the like from the surface of the semiconductor wafer, and also relates to an apparatus using this method.
(2) Description of the Related Art
As means to thin a semiconductor wafer (hereinafter, simply referred to as “wafer”), there are mechanical methods such as grinding and polishing and a chemical method utilizing etching. In working the wafer by utilizing these methods, in order to protect a surface of the wafer formed with a wiring pattern, a protective tape is joined to the surface. The wafer on which the protective tape has been joined and which has been subjected to polishing is adhered to and held by a ring frame through a supporting adhesive tape from a back face. Then, the protective tape is separated and removed from the surface of the wafer held by the ring frame.
As a method for separating and removing the protective tape, there is a known method in which a separating adhesive tape or the like is joined to a surface of the protective tape through a joining member such as a roller or an edge member and is separated, removed, and reeled together with the protective tape from the surface of the wafer by separating the separating adhesive tape or the like (for example, see JP-A 05-63077 (1993)).
However, the aforementioned conventional protective tape separating method has the following problems.
In recent years, there is a demand for a thinner wafer so as to permit high-density packaging as applications progress rapidly and the wafer has been thinned to 150 μm or less. Therefore, in the semiconductor wafer adhered and held at a center of the ring frame through the supporting adhesive tape, a height from an adhesive face of the supporting adhesive tape exposed between the wafer and the ring frame to the surface of the wafer is low. As a result, when the separating adhesive tape or the like is wound on the joining member such as the roller and the edge member and joined to the protective tape joined to the surface of the wafer held by the ring frame, the separating adhesive tape or the like falls at an end edge of the wafer and the adhesive face of the supporting adhesive tape and an adhesive face of the separating adhesive tape or the like adhere to each other. If the separating adhesive tape or the like is separated in this state, the wafer is lifted together with the supporting adhesive tape and broken.
If the joining member is stopped before the end edge of the wafer so as to avoid the above problem, the separating adhesive tape or the like is not joined at the end edge of the protective tape. If the separating adhesive tape or the like is separated in this state, the protective tape cannot smoothly be separated from the end edge and a separation error may occur.